'A Perfect Storm' has a lot to answer for...
However, in answer to your question:
Some helicopters can inflight refuel in the same way as FW aircraft, though in UK I think it's just Mk3 Chinook (not sure about Mk2) and possibly Merlin too (anyone from Freak Sqn care to help?).
Main trouble is finding a tanker that can fly slow enough to allow the helicopter to keep up. UK no longer has C130 ac capable of tanking as far as I know, and our jet tankers fly too fast.
Close formation in helicopter is slightly trickier than FW, but just requires practice. Downwash shouldn't be a player in AAR as it should be well behind the helicopter.
Tip strikes are possible. I've seen video footage of MH53 cutting off its own refuelling probe when pilot was a bit too eager to push forward cyclic to correct his position. Doh!!
I'm willing to stand corrected on all of this, as I haven't done it myself. The only AAR I've done has been hovering next to a ship, plugged into a hose! A Sea King can't keep up with much else...